Changes

Improvements to the test runners
1. Use `go list` to get list of integration dirs to build. This means we
  do not need to have a valid `.go` in every subdirectory and also
  filters out other dirs like "bundles" which may have been created. 2.
Add option to specify custom flags for integration and
  integration-cli. This is needed so both suites can be run AND set
  custom flags... since the cli suite does not support standard go
  flags. 3. Add options to skip an entire integration suite.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>